Stressful life experiences represent the most well-established environmental predictor of negative outcomes across the life-span. Research focused on children and adolescents, in particular, has documented a predictive relationship between stressors and both physical and psychological symptoms as well as academic problems. Despite the importance of the construct of stress, recent reviews of stress research indicate that incremental progress in the field has been limited as a result of inconsistent measurement of stress. A primary reason identified for inconsistent measurement is that existing measures do not provide a comprehensive system that addresses key criteria identified in the literature. These criteria include: a) assessment of contextual information that allows independent raters to agree the stressor would be threatening to the average child or adolescent (e.g., contextual information distinguishes between the experience death of a grandparent for a girl who had never met her grandmother from the experience of a girl who was reared by her grandmother); b) the opportunity for youth to answer questions outside of a face to face interview in order to reduce time demands associated with stress assessment and to reduce potential threats to validity based on youth's fears of providing information that could be embarrassing or have negative consequences if disclosed (e.g., if abuse is disclosed, a youth may be removed from his/ her home); c) measurement of stressors that range from minor events to broad systemic stressors; d) assessment of frequency, chronicity, and timing of experiences; and e) the opportunity to assess stress exposure in real time in order to assess immediate physiological, emotional, and cognitive responses. The proposed research will develop a stress measurement system that addresses all of these criteria through the pursuit of two specific aims: 1) Develop an integrated series of measures that assesses stress exposure and duration at multiple levels including systems level exposure, major event stressors, and minor stressors; 2) Use this newly developed stress measurement system to examine associations between multi-level stressors and both immediate responses (i.e., biological, cognitive, emotional) and broader outcomes (i.e., mental and physical health outcomes, academic and learning outcomes). The design will include experimental, daily diary, and short-term longitudinal methods, and the sample will consist of racially, ethnically, and socioeconomically diverse adolescents in order to capture both heightened stress exposure characteristic of this developmental period and specific systemic stressors common to youth of color. Once fully developed and validated, this measurement system will provide researchers with carefully constructed, comprehensive, and empirically- derived assessment tools for adolescent stressors. In the long term, understanding of stressors and their effects on physical and mental health and academic outcomes will improve our capacity to prevent the negative effects of stress on youth.